What is the Lamb's Book of Life, and How Do I Know if My Name is Written In it? #174

The Lamb's Book of Life is mentioned at least ten times in the Bible, and seems to be a book that was written before humans were created and contains the names of all of those who will inherit eternal life and be allowed into the City of God. Alarmingly, those who's names aren't written in the Book of Life are cast into the lake of fire. What does the Bible tell us about the Lamb's Book of Life, and how can we possible be sure our names are in it?